Isn't it pretty well established now, that some of these hypotheses just aren't very likely to happen?
A few decades ago, before we knew that the expansion of the Universe was accelerating, there were theories like 'The Big Crunch', which posited that the Universe was oscillating, and that it would ultimately contract to an infinitesimally small point, before starting over again. In fact, this suggested that perhaps the process had already happened an infinite number of times before. I always found this quite a poetic hypothesis, so it's a shame that we now know that it's rubbish!
The most commonly held theory today, amongst those who study such things, is the 'Big Freeze' model. This suggests that, although new stars are forming and being born all the time, eventually the Universe will run out of the materials needed to produce new stars, and as existing stars die - some becoming black holes - the matter of the Universe will be swallowed up. Black holes themselves have a finite lifespan, so eventually they too will go, possibly leaving only mysterious anti-matter like Dark Energy and Dark Matter.
Won't happen for a few trillion years though, so probably not much point in getting too anxious about it.

Ok I think I explain this once before so I do not feel like repeating it for this thread, so short version.

Universe is Expanding, after some time long after earth sees to exist, the universe will start to reseed / shrink . Once all the matter has gather in a small point the heat and pressure build up from it will create what is known as a BIG BANG, this lead to a new Universe being created from the old one, this has happen before evidence can be found by glancing at the Super giant Black Hole found in the center of are universe.

This is also known as the big bounce theory, and it is what most as in 98% the scientist at this time agree on.

I believe that this hypothesis (which I've heard called 'The Big Crunch') has been largely dismissed now. Since we discovered, several decades ago, that the expansion of the Universe is speeding up and not, as assumed, slowing, the idea of an oscillating Universe seems highly unlikely. I always quite liked it, because it seemed a very elegant model, but a vast majority of Cosmologists now disregard it as a failed model.

Since we do not fully understand the true nature of space and time, an expanding universe does not necessarily preclude the possibility of 'The Big Crunch'. If we assume, everything originated from a single point, 'The Big Bang' and expands outwardly for an infinite amount of time. If we also assume time and space is curved (like the surface of a sphere) all matter and energy would eventually coalesce at a single point resulting in another ' Big Bang' .

This is my personal opinion and not based on any scientific fact, but I believe in an eternally cyclical Universe. Perhaps it is a just a poetic hope, but any other end for this Universe seems so sad.